Chemotherapy has a major role in many childhood CNS tumors. In which of the following tumors is chemotherapy not effective?

Correct Answer: A

Rationale: In pediatric oncology, chemotherapy plays a vital role in the treatment of many CNS tumors. The correct answer is A) pilocytic astrocytoma. Pilocytic astrocytomas are generally low-grade tumors that are typically slow-growing and well-differentiated. They are often surgically resectable and have a good prognosis. Due to their characteristics, they are less responsive to chemotherapy compared to other more aggressive CNS tumors. Option B) craniopharyngioma is a benign tumor that is usually treated with a combination of surgery and radiation therapy. Chemotherapy is not typically the first-line treatment for craniopharyngiomas. Option C) pineoblastoma is a highly malignant and aggressive brain tumor that does respond to chemotherapy. Chemotherapy is an essential component of the treatment regimen for pineoblastomas. Option D) supratentorial primitive neuroectodermal tumors (SPNETs) are aggressive malignant brain tumors that are typically treated with a combination of surgery, radiation therapy, and chemotherapy. Chemotherapy is effective in the treatment of SPNETs. In an educational context, understanding the role of chemotherapy in the treatment of pediatric CNS tumors is crucial for healthcare professionals caring for pediatric patients with cancer. Knowing the specific tumor types that are more or less responsive to chemotherapy helps in tailoring treatment plans and managing patient expectations regarding outcomes and side effects of treatment.

Correct Answer: C

Rationale: In understanding why etoposide is the most likely cause of secondary acute myelogenous leukemia (AML) in the 9-year-old boy, we need to consider the drug's mechanism of action. Etoposide is a topoisomerase II inhibitor, which can lead to DNA damage and chromosomal translocations associated with the development of secondary malignancies like AML. Regarding the other options: A) Cyclophosphamide is alkylating agent associated with secondary malignancies but less commonly linked to AML compared to etoposide. B) Vincristine is a microtubule inhibitor and is not typically associated with secondary AML. D) Doxorubicin is an anthracycline that can cause secondary leukemias, but etoposide has a stronger association with AML development. Educationally, this question highlights the importance of understanding the long-term effects of chemotherapy in pediatric oncology patients. Healthcare providers need to be aware of the potential risks associated with different chemotherapeutic agents to provide comprehensive care and long-term surveillance for these vulnerable patients.

Correct Answer: D

Rationale: In anaplastic large cell lymphoma (ALCL), primary mediastinal involvement is more specific compared to other types of non-Hodgkin lymphoma. The characteristic presentation of ALCL often includes a mass in the mediastinum. This is due to the high expression of the CD30 antigen in ALCL cells, leading to a propensity for mediastinal lymph node involvement. This feature helps differentiate ALCL from other lymphomas. Option A, primary bone marrow involvement, is not specific to ALCL and can be seen in various lymphomas. Option B, intestinal involvement, is more typical of other types of lymphoma such as mucosa-associated lymphoid tissue (MALT) lymphoma. Option C, CNS involvement, is more commonly associated with lymphomas like Burkitt lymphoma or primary CNS lymphoma. Educationally, understanding the distinct clinical features of different types of lymphomas is crucial for accurate diagnosis and appropriate management. Recognizing specific manifestations like primary mediastinal involvement in ALCL can aid healthcare providers in providing targeted care and optimizing patient outcomes.

Correct Answer: B

Rationale: In this scenario, the BEST therapeutic approach for a 2-year-old child with a ruptured Wilms tumor is concomitant chemotherapy-radiotherapy (Option B). This approach is chosen because Wilms tumor is a type of kidney cancer that commonly affects children, and a multimodal treatment plan involving both chemotherapy and radiotherapy has been shown to be the most effective in improving survival rates and reducing the risk of recurrence. Option A, radiotherapy alone, is not the preferred treatment because Wilms tumor typically requires a combination of chemotherapy and radiotherapy for optimal outcomes. Option C, another surgery, is not the immediate course of action for a ruptured Wilms tumor as the primary treatment involves a combination of chemotherapy and radiotherapy. Option D, observation, is not suitable in this case as Wilms tumor is an aggressive cancer that requires prompt and aggressive treatment to improve outcomes. Educationally, it is crucial for healthcare providers, especially those specializing in pediatric oncology, to understand the importance of multimodal treatment approaches in managing pediatric cancers like Wilms tumor. This case emphasizes the significance of evidence-based practice and multidisciplinary collaboration in providing the best possible care for pediatric oncology patients.

Correct Answer: C

Rationale: In this scenario, option C, stating that supraphysiologic levothyroxine therapy is required during long-term follow-up, is the most appropriate statement to include in the discussion with the parents of a 12-year-old girl diagnosed with papillary thyroid carcinoma (PTC). The rationale for choosing option C is that children with PTC often require thyroid hormone replacement therapy to suppress thyroid-stimulating hormone (TSH) levels, which can help prevent the recurrence of cancer. Supraphysiologic doses of levothyroxine are often necessary to achieve this goal, making this statement crucial for the long-term management of the condition. Option A is incorrect because PTC, while a serious condition, does not necessarily have a grim overall prognosis, especially with appropriate treatment and follow-up care. Option B is incorrect because radioactive iodine therapy is commonly used in the treatment of differentiated thyroid cancers like PTC. Option D is incorrect because calcitonin/carcinogenic antigen monitoring is more relevant for medullary thyroid carcinoma, not papillary thyroid carcinoma. In an educational context, understanding the specific management strategies and follow-up care for pediatric patients with papillary thyroid carcinoma is essential for healthcare providers working with this population. Providing accurate information to parents and caregivers can help them better understand the treatment plan and support the long-term health and well-being of their child.